Tool for raising overcoils on hairsprings



Aug. 26, i c. MARTENSON v TOOL FOR RAISING OVERCOILS ON HAIR SPRINGS Filed March 6, 1945 E1 2) en 2702*.

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Patented Aug. 26, 1947 UNIT D STATES PATENT OFFICE.

TOOL FOR RAISING QVERCOILS ON HAIRSPRINGS' Carl Martenson, Walthain, Mass. I

Application March 6, 1945, Serial N01 581,215 r V I 4 Claims. 01. 81--6) This invention relates to'a tool forraising overcoils on hair springs of the type used in watches andclocks. Such springs are tiny spirally wound metal ribbons usuallymounted on a central collar and having a free outside convolution end. In assembling the'hair spring in a watch, for instance, the outside freeend is brought diametrically across the spring, sometimes passing through suitable apertures in thecollar and then anchored at the opposite side of the spring, the collar being frictionally engaged on the escapement shaft. To insure that this end will not contact the rest of the spring, the end is bent upwardly out of the plane of the spring in the form of an overcoil. Since the spring stock is in the form of a ribbon, this requires bending the stock in the plane of its width. The operation involves two bends, one to raise the ribbon and a second to bend back the stock so that the extended tail portion lies in a plane parallel with the plane of the remainder of the spring.

It is desirable and conventional to form this overcoil without disturbing the symmetrical spiral configuration of the spring even as to the overcoil portion.

Such overcoil raising operation has been commonly done either by hand or by a, two-step die operation, the first step involving bending the tail up and the second step involving turning the spring over and reinserting the end convolution in the die to bend the tail portion back into a plane parallel with the rest of the spring.

The object of this invention is to provide a tool for forming both bends in the stock in a onestep operation with precision and dispatch, thus reducing labor cost and waste in overcoil raising operations.

The type of overcoil hair spring with which this invention deals is illustrated in the accompanying drawings which also show the too-l of this invention and in which Fig. 1 is a greatly enlarged perspective View of a hair spring prior to the operation of raising an overcoil;

Fig. 2 is a perspective View of the hair spring of Fig. 1 after an overcoil has been raised thereon;

Fig. 3 is an elevation of the spring shown in Fig. 2;

Fig. 4 is an elevation broken away centrally showing the tool of this invention on a scale enlarged about three times; a

Fig. 5 is a, partial elevational view of the tool on the side opposite that shown in Fig. 4;

Fig. 6 is a still furtherenlarged exploded detail of certain of the operating parts of the tool of Fig. 4; 1

Fig. 7 is an enlarged vertical section through the operating parts taken along the line 1-1 of Fig. 4, after the operating parts have been moved to'a relatively closer position than that shown in Fig. 4; I v

Fig. 8 is a cross-sectional view similar to that shown in Fig. 7 after the operating parts have been moved towards each other to their limit of movement; and

Fig. 9 is a cross-sectional view taken along the line 9-9 of Fig. 8 and showing a horizontal section of the operating parts in the position of their limit 'of movement.

As shown in Figs. 1 to 3, a hair spring comprising aspirally coiled steel or non-magnetic alloy ribbon l9 mounted on a central collar l l is formed by the tool of this invention to the configuration shown in Figs. 2 and3, wherein the tail G2, or free end of outer convolution Q3, of spring it? is raised upwardly out of the plane of the rest of the spring to form an overcoil. lying in a plane parallel to but spaced from the plane of the rest of the coil.v

The overcoil is formed as shown by impressing a reverse bend inthe coil without disturbing the symmetrical spiral relation of the spring and its overcoil tail. Generally the overcoil is formed in such position that the overcoilincludes a section of the outside convolution equivalent to an arc of about 120 to 270.

The tool of this invention is shown in Figs. 4 to 9 and comprises two pincer-like arms I4 and I6 mounted for resilient movement relative to one another by the interposition therebetween at one of their ends of spacing wedge I3 through which passes an assembling and retaining screw 25. The arms l4 and [6 are provided with cooperating longitudinal guide means in the form of a guide 22 fixed to upper arm l4 and a slot '24 formed in bottom arm 6 for accommodating the guide 22 during movement of the arms l4 and is relative to one another. Arms [4 and I6 are also provided with means for limiting their converging and diverging movement, including an adjustable limit screw 25 depending from upper arm M and adapted to bear against the top surface of lower arm I 6 to limit movement of the arms towards each other; and an adjustable limit screw 28 I countersunk in upper arm M so that the head threaded into lower arm l6 and being loosely of screw 23 bears against the abutment of the countersunk recess in arm I l during diverging movement of the arms to form a positive limit for such movement.

Arms M and I6 terminate in operating jaws or dies which include, respectively, bosses 30 and 3!, boss 30 extending downwardly from arm l4 and boss 31 extending upwardly from arm I6. Each boss has formed therein a transverse slot. As shown particularly in Fig. 9, these slots 32 and 33 are cut on a radius that conforms generally with the radius of the outer convolution [3 of a spring to be overcoiled and are in arcuate alignment as the arms are moved toward each other to'operating position with inner edges of bosses 30 and 3! moving closely adjacent to each other. Each of the bosses 3t and 3| carries a pin 35 and 36, respectively, passing transversely of the slot therein. The pins 35 and 36 serve to decrease the depthof the slots at points spaced inwardly from the ends of the slots adjacent to the other die. This inward spacing of the points of minimum depth of the slots serves to cause the slots to make contact with the hair spring at spaced points so that the bends in the spring are spaced from each other, as shown in Fig. 8, to raise the overcoil above the plane of the hair spring.

'M'ountedon the outside of both arms Li and it are 'identical'oppositely extending guide plates 40 and M. These plates comprise flat steel plates, which have areas of reduced thickness in which are formed slots #2 and 53 respectively. Each of the plates has an arcuate slot M adapted to accommodat a screw 40 passing through a washer 4-? and fastening the two plates 40 and a: to the respective arms l and it. As indicated particularly in Figs. '7, 8 and 9, as mounted, each of these plates is spaced laterally from the path of movement of the adjacent boss 30 or 3 I.

The purpose of the arcuat slots Mi is to permit the plates 40 and 4| to be adjustably mounted on the arms I l and I6, and as shown in Figs. 4 and 5, each plate is so adjusted relative to its arm is and it that its slot &2 or 43 is inclined inwardly of the tool for a purpose to be presently described. The mounting is such, however, that the open ends of slots 12 and 43 may always be positioned in general arcuate alignment with the openings of slots 32 and 33. The inclination of the slots (52 and d3 is exaggerated in Figs. 4 and for the purposes of explanation of the invention.

With the tool thus formed an outside convolution of a hair spring it may be passed through the channels formed by the slots 33 and 42 of bottom arm I5 and pressure may then be applied to the two arms to close the upper arm l4 die onto the spring so that the slots 43 and 32 accommodate the spring which is brought to the position shown in Fig. '7. Because of the inclination of the plates 40 and 5!, it will be seen that the steel ribbon is inclined slightly one way by the plate 40 and slightly the other way by the plate 4! as shown in Fig. '7, thus imparting a tensioning twist to the portions of the spring on each side of the bosses 33 and .3 I.

As the jaws are moved towards each other from the position shown in Fig. '7 to the position shown in Fig. 8 and to the limit of converging movement of the arms l4 and it as controlled by the limit screw 26, pins 35 and 36 bear against spaced portions of the end convolution 53 from above and below respectively, imparting a simultaneous reverse bend to the portion of the spring enveloped b the two bosses. During this movement the tension on the portion of the spring being op- 'erated upon is maintained by the continued movement of the plates 40 and ll. However, it will be found that during the operation the plane of the spring inclines itself due to the pressure of the pins 30 and 35 so that in general the tension on the spring remains substantially that originally imparted by movement of the cooperating jaws of the tool to the position shown in Fig. 7.

I hav found that in order to insure that the tail of the overcoil remains in a plane parallel to that of the rest of the spring, it is essential that tension be imparted to the spring during the forming operation as by some such means as the inclined guide slots t2 and 03.

After the arms I l and H5 have been brought to the limit of their movement and to the position shown in Fig. 8, the arms may be released and by reason of their resilient mounting, will return to the position shown in Fig. 4 permitting the spring to be removed from the tool with its configuration conforming to that shown in Figs. 2 and 3.

The operation is most rapid, especially after one has attained skill in positioning the end convolution 53 in the bottom slots 33 and 42 as the initial step in the operation.

spring, the overcoil of which may be formed by the use of a tool such as that described, has a ribbon width of about .25 mm. and a thickness of about .007 mm. The slots of a tool for use with such springs can then have a width of about .009 mm. and the distance between vertical planes passing through the axes of pins 35 and (35 can be approximately 0.70 mm.

It will be understood that the height of the overcoil may be varied by adjustment of stop screw 26 controlling the amount of overlap of pins 35 and 36 at the limit of movement of arms l4 and it towards each other.

I claim:

1. An overcoil raisingtool for hair springs comprising a pair of opposed dies of substantial width connected to each other for relative movement from relatively remote loading positions to overlapping closely adjacent side by side working positions, said dies presenting transverse slots for accommodating a convolution of a hair spring edgewise, said slots being of such depth as to overlap in alignment when said dies are brought to working position, the depth of each slotat a point spaced inwardly from its end adjacent the other die being less than the depth at said end, and slotted guides connected to the dies and movable therewith, the guide connected to one die being adjacent to and laterally spaced from the outer side of the other die, with its slot adjacent to the slot in the other die, the slots of said guides extending in the same general direction, and said guides being adapted to accommodate edgewise and to guide portions of a hair spring being acted upon by said dies.

2. An overcoil raising tool for hair springs as claimed in claim 1 wherein the slotted guides are adjustably mountedon said dies.

3. An overcoil raising tool for hair springs as claimed in claim 1 wherein the slotted guides are augularly adjustably mounted on said dies and are adjusted so that the slots therein are angularly related to the slots in the dies, said tool including means for locking the slotted guides in angularly adjusted position.

l. An overcoil raising tool for hair springs as claimed in claim 1 wherein the slotted guides are 6 angularly adj ustably mounted on said dies and are adjusted so that the slot in one guide is angularly UNITED STATES PATENTS inclined in one direction with respect to the slot Number Name Date in th die with which it moves and the slot in the 615,035 Moss Nov. 29, 1898 other guide is angularly inclined in the opposite 5 792,367 o sen e 13, 19 5 direction with respect to the slot in th die with ,6 7,108 Gruber July 26, 1927 which it moves, whereby said guides impart ten- 753,043 MOineaUX 1904 sioned twist to portions of a spring convolution extending between the slots in said guides, said FOREIGN PATENTS tool including means for locking the slotted guides 10 Nu b Country e in angularly adjusted position. 202,947 Germany July 12, 1907 CARL MARTENSON.

REFERENCES CITED The following references are of record in the 15 file of this patent: 

